1. Technical Field
The present invention relates to a pharmaceutical composition in the form of an aqueous solution with improved photostability which comprises as an active ingredient a benzyl alcohol compound having excellent stimulating activity on an adrenergic .beta..sub.2 -receptor and useful as a uterine relaxing agent, bladder relaxing agent and the like.
2. Background Art
Optically active (-)-(R)-.alpha.-[(tert-butylamino)methyl]-2-chloro-4-hydroxybenzyl alcohol (hereinafter referred to as "the present compound") represented by the following formula (I): ##STR2## and pharmacologically acceptable salts thereof, which have uterine relaxing activity, bladder relaxing activity and other, have been revealed useful as a therapeutic medicament for threatened premature delivery or a therapeutic medicament for urination disorders such as urinary incontinence, nocturnal enuresis or the like (Japanese Patent Unexamined Publication No. (Hei) 178356/1992).